In the mid 70's, as homes became tighter and tighter to conserve energy, we started to devise mechanical means to bring fresh air into the home on a predictable basis to ensure air quality. There are many ways to achieve this, and I am not going to discuss all of the different systems in detail. The building codes eventually "required" some means of changing the air at prescribed rates in all new construction and homes that were being substantially remodeled.
Sometimes the system is a stand-alone unit with its own ductwork----like a "Heat Recovery Unit." These systems are really cool because in the Winter they exchange the heat in the outgoing air into the cold incoming air (and just the opposite in the Summer).
Other times it is tied into a bathroom or laundry exhaust fan and there will be a timer located in the home that can be set so the fan turns on periodically.
Another method is for it to be tied into the forced air furnace system. This type of system utilizes an air intake installed in the return air duct of the furnace with an automatic damper that is controlled by the furnace circuit board, timer and thermostat. Here is what the automatic damper control might look like at the intake pipe in an attic.
This is a very efficient way to bring fresh air into the home if you have a forced air system----although all of the different methods have their issues. One of the advantages of this system is that the air in the home is filtered year round----not just in the winter when the furnace is operating. And, because it utilizes the ductwork of the furnace heating system, fresh air is distributed to all the rooms in the home.
Several times a year I find this particular type of system compromised because of lack of communication between the roofer and the heating contractor. For the air intake to work properly it has to be able to bring in air when the automatic damper opens and the furnace blower kicks on to pull in air. The roofer knows that the air-intake pipe needs a roof cap----so they install a typical roof vent cap----with a back draft damper in it----designed to move air out of the house not into it. While the vent cap itself is most likely adequate----the damper must be removed for any air to move into the system. A simple enough repair---but the damper in this cap has been installed this way for 10 years.
The flat plate-like flap of the damper can be seen behind the screen in the picture.
Charles Buell
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Charles - very interesting post. I always enjoy reading your blog.
Good info. I have to see where the vent is on my home. Thank you for the post.
Lisa, glad you like it---keep on visiting:)
Jan, it seems a lot of my blogs get people running all over their houses looking for things. (Note to self: Maybe I should do a blog about all the places people hide money:)
Great post as always Charles. Today I am also looking for some advice. A young man recently asked me if he should enroll in classes to become a licensed home inspector, he doesn't know if the time and money is worth it.
He says he has experience in the trades and has purchased four homes all of which he personally rehabbed.
His specific questions included:
Does it make sense to become a Home Inspector right now?
Is the market flooded with inspectors? Do brokers, banks, etc., use the same inspectors with all inspections?
I figured you would be a great person to ask. Let me know what you think, I really appreciate it.
Ilyce
Ilyce, I can't speak too well for the State Illinois, but my feeling is that there is always a need for really good inspectors especially given that some of the existing inspectors are not very good. A lot of inspectors have dropped out and that creates some need as the market improves. I would advice him to take a really hard look at the big picture. Does he for example realize that what he knows is only part of what it takes to make a good inspector. How he writes and how he deals with people; and, how he writes and how he deals with people is more important:) You can always learn stuff----but if you aren't a people person you will have trouble. Hopefully I can get my buddy Steve (who is the coordinator for the Home Inspection Training Class that we both teach at) to respond to your questions.
Ilyce,
I do not think there is a shortage of inspectors. Although it probably varies in different areas. As Charlie mentioned, there is a real variation in the quality of inspectors. My experience is that, often, someone who worked in the trades is not necessarily the best candidate to be successful in the field. However, with formal inspection training in other areas the chances of success increase. I think, basically, what Charlie said is the best answer. As far as the market, it is the same story, some complain they have zero work while others are busy. It depends on the person, the quality of their work, their personality and their marketing. Not getting sued helps too.
Thank you Charles and Steven for all of the advice. I will let you know how it goes with the young prospective home inspector! I really appreciate your help.
Ilyce